US4436712A - Method of removing hydrogen sulfide from gases utilizing a polyvalent metal chelate of nitrilotriacetic acid and electrolytically regenerating the solution - Google Patents

Method of removing hydrogen sulfide from gases utilizing a polyvalent metal chelate of nitrilotriacetic acid and electrolytically regenerating the solution Download PDF

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US4436712A
US4436712A US06/429,958 US42995882A US4436712A US 4436712 A US4436712 A US 4436712A US 42995882 A US42995882 A US 42995882A US 4436712 A US4436712 A US 4436712A
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polyvalent metal
nitrilotriacetic acid
metal chelate
cathode
admixture
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Donald C. Olson
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Shell USA Inc
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Shell Oil Co
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Priority to US06/429,958 priority Critical patent/US4436712A/en
Priority to DE8383201256T priority patent/DE3363770D1/de
Priority to EP19830201256 priority patent/EP0107213B1/en
Priority to CA000436391A priority patent/CA1245179A/en
Priority to AU19667/83A priority patent/AU561202B2/en
Priority to JP58178346A priority patent/JPS5982925A/ja
Assigned to SHELL OIL COMPANY A DE CORP reassignment SHELL OIL COMPANY A DE CORP ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: OLSON, DONALD C.
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B01D53/1493—Selection of liquid materials for use as absorbents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B01D53/1425—Regeneration of liquid absorbents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B01D53/1456—Removing acid components
    • B01D53/1468—Removing hydrogen sulfide
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B17/00—Sulfur; Compounds thereof
    • C01B17/02—Preparation of sulfur; Purification
    • C01B17/04—Preparation of sulfur; Purification from gaseous sulfur compounds including gaseous sulfides
    • C01B17/05—Preparation of sulfur; Purification from gaseous sulfur compounds including gaseous sulfides by wet processes

Definitions

  • the sour gas is contacted, preferably with a solvent-reactant system which comprises a regenerable reactant, to produce solid free sulfur which is recovered either prior or subsequent to regeneration.
  • Suitable reactant materials include polyvalent metallic ions, such as iron, vanadium, copper, manganese, and nickel, and include polyvalent metal chelates.
  • Preferred reactants are coordination complexes in which iron forms chelates with specified organic ligands.
  • CO 2 present in the gaseous stream is also removed by the use of a suitable selective absorbent.
  • the invention relates to a process for the removal of H 2 S from a sour gaseous stream comprising contacting the sour gaseous stream in a contacting zone with an aqueous reaction solution or mixture at a temperature below the melting point of sulfur, the aqueous reaction solution or mixture comprising an effective amount of an oxidizing polyvalent metal chelate, or mixtures thereof, of nitrilotriacetic acid, producing a reactant admixture containing sulfur and reduced polyvalent metal chelate or chelates of nitrilotriacetic acid, and regenerating the reactant admixture electrolytically, as hereinafter described.
  • a sweet gas stream is produced, and elemental sulfur is recovered.
  • the regeneration may be carried out directly in the contacting zone, while in a preferred embodiment, an aqueous reactant admixture containing reduced polyvalent metal chelate or chelates is removed from the contact zone and electrolytically, as herein specified, regenerated in a separate zone. At least a portion of the sulfur crystals may be removed before regenerating the reduced reactant (preferred), or at least a portion of the sulfur crystals may be removed after regeneration.
  • a sour gaseous stream containing H 2 S and CO 2 is contacted with a selective absorbent-aqueous reactant mixture at a temperature below the melting point of sulfur, the reactant mixture and procedure being similar to that described, supra.
  • this is accomplished by the use of an absorbent mixture containing a selective absorbent for CO 2 (and preferably for H 2 S, as well), and an effective amount of an oxidizing polyvalent metal chelate or chelates of nitrilotriacetic acid.
  • a purified or "sweet" gaseous stream is produced which meets general industrial and commercial H 2 S and CO 2 specifications.
  • the CO 2 is absorbed and the H 2 S is immediately converted to sulfur by the oxidizing polyvalent metal chelate or chelates.
  • the polyvalent metal chelate or chelates are reduced, and the sulfur may be treated, as described, supra.
  • the sulfur crystals may be removed prior or subsequent to electrolytic regeneration of the admixture.
  • the invention also provides, in this embodiment, for the regeneration of the reactant and the absorbent.
  • the loaded absorbent mixture containing the reduced chelate or chelates is regenerated in an electrolytic regeneration zone or zones, as described.
  • the reactant-containing solution is treated prior or subsequent to electrolytic regeneration, such as by heating or pressure reduction, to remove the CO 2 (either prior or subsequent to sulfur removal).
  • a key feature of the invention lies in the manner in which the regeneration of the reduced polyvalent metal chelate or chelates of nitrilotriacetic acid is carried out.
  • a suitable electrode or electrodes are maintained in the solution or admixture in the contacting zone, preferably at some finite distance from the site of the introduction of the H 2 S, and direct current, such as from a potentiostat, is supplied to such electrode(s) as an anode, a separate half cell containing a suitable cathode or cathodes also being provided. Allowance is made for passage of hydrogen ion from the contacting zone to the cathode(s), and hydrogen is produced at the cathode(s).
  • the H 2 S removal and regeneration of the reduced chelate or chelates is carried out continuously.
  • the solution or admixture containing reduced polyvalent metal chelate or chelates is removed from the contact zone, sulfur is removed, and the reduced metal chelate or chelates are oxidized by passing the admixture through the anode section of an electrochemical cell supplied from a source of potential, the anode removing electrons from the reduced metal chelate or chelates and converting the chelate or chelates to the oxidized or higher valence metal chelate or chelates.
  • the other half cell is used to produce hydrogen.
  • a similar procedure may be employed if a selective absorbent aqueous reactant mixture is employed.
  • the process, including the regeneration, is preferably carried out continuously, and the cells may be employed in series.
  • a variety of half cells may be employed in the practice of the invention. Any suitable hydrogen producing half cell may be coupled. Such half cells, are known, and form, per se, no part of the invention. Generally, the anode and cathode will be separated by a suitable barrier to prevent reduction of the oxidized polyvalent metal chelate or chelates, the barrier, however, allowing or permitting hydrogen ion transport. Suitable barriers may be selected by those skilled in the art, and include porous or fibrous non-conductive inert materials containing or impregnated with the desired electrolyte. For example, asbestos cloth and microporous polyvinyl chloride may be employed. However, polymeric ion exchange membranes, which also function as electrolytes, may be used to separate the electrodes.
  • Nafion a perfluorinated carbon polymer with pendant sulfonic groups, as described in IECEC '75 (Intersociety Energy Conversion Engineering Conference) Record, pages 210 through 216, is suitable.
  • Suitable electrodes include, e.g., platinum and carbon, and the hydrogen producing half cell may be as varied, as for example, a carbon electrode in H 2 SO 4 , phosphoric acid, or other acidic electrolytes, or an ion exchange electrolyte such as Nafion with platinum or other suitable electrode material deposited thereon.
  • the reaction may be shown, in the case of iron, as follows:
  • gaseous stream treated is not critical, as will be evident to those skilled in the art.
  • Streams particularly suited to removal of H 2 S and CO 2 by the practice of the invention are, as indicated, naturally-occurring gases, synthesis gases, process gases, and fuel gases produced by gasification procedures, e.g., gases produced by the gasification of coal, petroleum, shale, tar sands, etc.
  • gasification procedures e.g., gases produced by the gasification of coal, petroleum, shale, tar sands, etc.
  • coal gasification streams, natural gas streams and refinery feedstocks composed of gaseous hydrocarbon streams especially those streams of this type having a low ratio of H 2 S to CO 2 , and other gaseous hydrocarbon streams.
  • hydrocarbon stream(s) is intended to include streams containing significant quantities of hydrocarbon (both paraffinic and aromatic), it being recognized that such streams contain significant "impurities" not technically defined as a hydrocarbon.
  • streams containing principally a single hydrocarbon, e.g., ethane are eminently suited to the practice of the invention.
  • Streams derived from the gasification and/or partial oxidation of gaseous or liquid hydrocarbon may be treated by the invention.
  • the H 2 S content of the type of streams contemplated will vary extensively, but, in general, will range from about 0.1 percent to about 10 percent by volume. CO 2 content may also vary, but may range from about 0.1 percent to about 99 percent or greater by volume. Obviously, the amounts of H 2 S and CO 2 present are not generally a limiting factor in the practice of the invention.
  • the temperatures employed in the contacting or absorption-contact zone are not generally critical, except that the reaction is carried out below the melting point of sulfur, and, if an absorbent is used, the temperatures employed must permit acceptable absorption of CO 2 .
  • absorption at ambient temperatures is desired, since the cost of refrigeration would exceed the benefits obtained due to increased absorption at the lower temperature.
  • temperatures from 10° C. to 80° C. are suitable, and temperatures from 20° C. to 45° C. are preferred.
  • Contact times will range from about 1 second to about 270 seconds or longer, with contact times of 2 seconds to 120 seconds being preferred.
  • temperatures may be varied widely.
  • the regneration zone should be maintained at substantially the same temperature as the contacting zone.
  • temperatures of from about 10° C. to 80° C., preferably 20° C. to 45° C., may be employed.
  • Pressure conditions in the contacting zone may vary widely. If the regeneration is carried out in the contacting zone, the pressure may vary up to the limitations of the electrolytic half cell. If the regeneration is carried out in a separate zone, pressures in the contacting zone may vary from one atmosphere up to one hundred fifty or even two hundred atmospheres, with pressures of from one atmosphere to about one hundred atmospheres being preferred. In the regeneration or desorption zone or zones, pressures also may be varied considerably, and will preferably range from about 0.5 atmosphere to about three or four atmospheres. The pressure-temperature relationships involved are well understood by those skilled in the art, and need not be detailed herein. Other conditions of operation for this type of reaction process, e.g., pH, etc., are further described in U.S. Pat. No.
  • pH in the process of the invention will be in the acid region, i.e., less than 7.
  • the H 2 S when contacted, is rapidly converted in the process of the invention by the oxidizing polyvalent metal chelate or chelates of nitrilotriacetic acid to elemental sulfur. Since the chelates have limited solubility in many solvents or absorbents, if an absorbent is used, the chelate or chelates are preferably supplied in admixture with the liquid absorbent and water.
  • the amount of the oxidizing polyvalent metal chelate, or mixtures thereof, supplied is an effective amount, i.e., an amount sufficient to convert all or substantially all of the H 2 S in the gas stream, and will generally be on the order of at least about one mol per mol of H 2 S.
  • Ratios of from about 2 mols to about 15 mols polyvalent metal chelate per mol of H 2 S converted (basis polyvalent metal) may be used, with ratios of from about 2 mols per mol to about 5 mols of polyvalent metal chelate or chelates per mol of H 2 S being preferred.
  • the manner of preparing the admixture containing an absorbent is a matter of choice.
  • the polyvalent metal chelate or chelates may be added to the absorbent, and, if necessary, then water added. The amount of water added will normally be just that amount necessary to achieve solution of the chelate or chelates, and can be determined by routine experimentation.
  • the polyvalent metal chelate or chelates may have a significant solubility in the solvent, and since water is produced by the reaction of the H 2 S and the oxidizing polyvalent metal of the chelate(s), precise amounts of water to be added cannot be given. In the case of absorbents having a low solubility for the chelate(s), approximately 5 percent to 10 percent water by volume, based on the total volume of the absorbent mixture, will generally provide solvency.
  • the polyvalent metal chelate or chelates are added as an aqueous solution to the liquid absorbent. Where the reactant is supplied as an aqueous solution, the amount of solution supplied may be about 20 percent to about 80 percent by volume of the total absorbent admixture supplied to the absorption zone.
  • An oxidizing polyvalent metal chelate solution will generally be supplied as an aqueous solution having a concentration of from about 0.1 molar to about 1 molar, and a concentration of about 1.0 molar is preferred.
  • the ligand to metal molar ratio may range from 1.1 to 2.0, preferably 1.2 to 1.4.
  • the oxidizing polyvalent metal chelates of nitrilotriacetic acid are employed in the invention.
  • Any oxidizing polyvalent metal chelate of NTA, or mixtures thereof, may be used, but those of iron, copper and manganese are preferred, particularly iron.
  • the polyvalent metal should be capable of oxidizing hydrogen sulfide, while being reduced itself from a higher to a lower valence state, and should then be oxidizable from the lower valence state to a higher valance state in a typical redox reaction.
  • Other polyvalent metals which can be used include lead, mercury, palladium, platinum, tungsten, nickel, chromium, cobalt, vanadium, titanium, zirconium, molybdenum, and tin.
  • the absorbents employed in this invention are those absorbents which have a high degree of selectivity in absorbing CO 2 (and preferably H 2 S as well) from the gaseous streams. Any of the known absorbents conventionally used which do not affect the activity of the polyvalent chelate, or mixtures thereof, and which exhibit sufficient solubility for the reactant or reactants may be employed. As indicated, the absorbent preferably has good absorbency for H 2 S as well, in order to assist in the removal of any H 2 S present in the gaseous streams. The particular absorbent chosen is a matter of choice, given these qualifications, and selection can be made by routine experimentation.
  • diethylene glycol mono ethyl-ether, propylene carbonate, tetraethylene glycol-dimethyl ether, N-methyl pyrrolidone, sulfolane, methyl isobutyl ketone, 2,4-pentanedione, 2,5-hexanedione, diacetone alcohol, hexyl acetate, cyclohexanone, mesityl oxide, and 4-methyl-4-methoxypentone-2 may be used.
  • Suitable temperature and pressure relationships for different CO 2 -selective absorbents are known, or can be calculated by those skilled in the art.
  • the sulfur may be recovered by settling, filtration, liquid extraction or flotation, or by suitable devices, such as a hydroclone.
  • the sulfur is removed prior to regeneration.
  • FIG. 1 illustrates the first embodiment of the invention
  • FIG. 2 illustrates a preferred H 2 S removal process regeneration system
  • FIG. 3 illustrates a preferred electrode system.
  • the gas preferably as fine bubbles, is contacted in contactor 2 with a 1.0 M solution of the ferric chelate of nitrilotriacetic acid.
  • the H 2 S is immediately converted to sulfur and H + ions, and ferric chelate of nitrilotriacetic acid is converted to ferrous chelate of nitrilotriacetic acid.
  • "Sweetened" natural gas passes overhead via line or outlet 4 to use as further treatment.
  • Contactor 2 also contains a platinum anode 5, which is connected electrically through a potential source 6 to a cathode 7.
  • Cathode 7 is mounted opposite an opening in the wall of contactor 2 in a chamber 10 which contains 0.1 to 1 M H 2 SO 4 in such manner that it is in contact with a hydrogen ion permeable membrane (8) which covers the opening.
  • the membrane (8) preferably comprises a substance, such as Nafion, and the cathode, which may simply be a porous carbon coating on the membrane, preferably contains platinum particles.
  • the reduced chelate As the reduced chelate is formed in solution, it is promptly oxidized at anode (5) by virtue of a potential of 2 volts being placed across the cell. Concomitantly, hydrogen ions migrate through the membrane, receive electrons at the carbon cathode, and form molecular hydrogen.
  • the hydrogen gas is removed via 11.
  • the procedure is preferably conducted continuously, sulfur-containing reactant solution being removed from the bottom of contactor (2), as shown, and passed via line (12) to filter (13) where sulfur is removed. Other means of sulfur removal may be provided. After sulfur removal, the solution is returned via line (14) to contactor 2.
  • sour gas e.g., natural gas containing about 0.5 percent H 2 S
  • contactor or column 2 into which also enters an aqueous admixture comprising an aqueous 1.0 M solution of the Fe(III)chelate of nitrilotriacetic acid from line 12.
  • the pressure of the feed gas is about 1200 p.s.i.g., and the temperature of the aqueous admixture is about 45° C.
  • a contact time of about 120 seconds is employed in order to react all the H 2 S.
  • Purified or "sweet" gas leaves column 2 through line 3.
  • the "sweet" gas is of a purity sufficient to meet standard requirements.
  • the H 2 S is converted to elemental sulfur by the Fe(III)chelate, Fe(III)chelate in the process being converted to the Fe(II)chelate.
  • the aqueous reactant admixture, containing the elemental sulfur is removed continuously and sent through line 4 to a depressurization and degassing unit 5, and then to a separation zone.
  • the separation zone 6 preferably comprises a unit, such as filter or centrifuge 6, for separating the bulk of the sulfur produced from the aqueous admixture. It is not necessary that all sulfur be removed from the admixture. Sulfur is removed via line 7, and may be further treated, as desired.
  • the aqueous admixture is removed via line 8 for regeneration of the chelate. If the aqueous admixture contains a solvent for CO 2 , according to that embodiment of the invention, it is suitably stripped at this point, or after regeneration (shown in dotted lines). If steam stripping is used, the solution must be cooled before re-use.
  • the admixture in line 8 enters the anode section A of cell 9 (direct current supplied, as shown) where the reduced reactant, i.e., the Fe(II)chelate of nitrilotriacetic acid is oxidized at a carbon electrode to the Fe(III)chelate of nitrilotriacetic acid.
  • a potential of 2 volts is utilized across the cell.
  • Regenerated reactant mixture leaves section A via line 10, preferably to a holding tank 11, from whence it may be returned via line 12 to contactor 2.
  • Section A is separated from cathode section C by a hydrogen ion permeable barrier B.
  • Section C receives H + ion from section A, and hydrogen is removed overhead via line 13.
  • FIG. 3 illustrates schematically another cell which may be used to produce hydrogen in the regeneration step of the invention.
  • the aqueous admixture enters the anode section A through line 20.
  • the cell has a potential of 2 to 3 volts across the electrodes.
  • the reduced iron (FeII)chelate of nitrilotriacetic acid is oxidized at the electrode to the Fe(III)chelate.
  • Regenerated aqueous reactant solution leaves section A through 21, and may be returned to the contact zone for further H 2 S removal.
  • H 2 is produced in cathode section C at a platinum electrode, and is removed through line 22.
  • the solution in this half cell is a 0.1 to 1 M solution of H 2 SO 4 , and this solution is separated from section A by an asbestos cloth barrier at B.

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  • Analytical Chemistry (AREA)
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  • Oil, Petroleum & Natural Gas (AREA)
  • Chemical Kinetics & Catalysis (AREA)
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  • Inorganic Chemistry (AREA)
  • Gas Separation By Absorption (AREA)
  • Treating Waste Gases (AREA)
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  • Fuel Cell (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
US06/429,958 1982-09-30 1982-09-30 Method of removing hydrogen sulfide from gases utilizing a polyvalent metal chelate of nitrilotriacetic acid and electrolytically regenerating the solution Expired - Lifetime US4436712A (en)

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Application Number Priority Date Filing Date Title
US06/429,958 US4436712A (en) 1982-09-30 1982-09-30 Method of removing hydrogen sulfide from gases utilizing a polyvalent metal chelate of nitrilotriacetic acid and electrolytically regenerating the solution
DE8383201256T DE3363770D1 (en) 1982-09-30 1983-08-31 H2s removal
EP19830201256 EP0107213B1 (en) 1982-09-30 1983-08-31 H2s removal
CA000436391A CA1245179A (en) 1982-09-30 1983-09-09 H.sub.2s removal with oxidizing polyvalent metal chelate and electrolytic regeneration thereof
AU19667/83A AU561202B2 (en) 1982-09-30 1983-09-28 Removal of hydrogen sulphide from a sour gas stream
JP58178346A JPS5982925A (ja) 1982-09-30 1983-09-28 硫化水素の除去

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US4643886A (en) * 1985-12-06 1987-02-17 The Dow Chemical Company Automatic pH control in a process for removal of hydrogen sulfide from a gas
US4832937A (en) * 1988-09-28 1989-05-23 The Dow Chemical Company Regeneration of chelated polyvalent metal solutions by controlled potential electrolysis
US4969986A (en) * 1988-09-28 1990-11-13 The Dow Chemical Company Controlled potential electrolysis apparatus
US8691413B2 (en) 2012-07-27 2014-04-08 Sun Catalytix Corporation Aqueous redox flow batteries featuring improved cell design characteristics
US8753761B2 (en) 2012-07-27 2014-06-17 Sun Catalytix Corporation Aqueous redox flow batteries comprising metal ligand coordination compounds
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US10497958B2 (en) 2016-12-14 2019-12-03 Lockheed Martin Energy, Llc Coordinatively unsaturated titanium catecholate complexes and processes associated therewith
US10644342B2 (en) 2016-03-03 2020-05-05 Lockheed Martin Energy, Llc Coordination complexes containing monosulfonated catecholate ligands and methods for producing the same
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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1034646A (en) 1910-04-04 1912-08-06 Gustav H Rabenalt Process of purifying hydrogen.
US2819950A (en) 1952-03-27 1958-01-14 Texas Gulf Sulphur Co Conversion of hydrogen sulfide to sulfur with quinones
US3068065A (en) 1956-08-24 1962-12-11 Humphreys & Glasgow Ltd Method of removing hydrogen sulphide from gases
US3580950A (en) 1967-11-01 1971-05-25 Frederick C Bersworth Chelating compositions based on chelating acids and amines
US3765946A (en) 1971-08-18 1973-10-16 United Aircraft Corp Fuel cell system
US4091073A (en) 1975-08-29 1978-05-23 Shell Oil Company Process for the removal of H2 S and CO2 from gaseous streams

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1034646A (en) 1910-04-04 1912-08-06 Gustav H Rabenalt Process of purifying hydrogen.
US2819950A (en) 1952-03-27 1958-01-14 Texas Gulf Sulphur Co Conversion of hydrogen sulfide to sulfur with quinones
US3068065A (en) 1956-08-24 1962-12-11 Humphreys & Glasgow Ltd Method of removing hydrogen sulphide from gases
US3580950A (en) 1967-11-01 1971-05-25 Frederick C Bersworth Chelating compositions based on chelating acids and amines
US3765946A (en) 1971-08-18 1973-10-16 United Aircraft Corp Fuel cell system
US4091073A (en) 1975-08-29 1978-05-23 Shell Oil Company Process for the removal of H2 S and CO2 from gaseous streams

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